Continuation of combined clinical and immunologic study of treatment in hay fever due to ragweed is proposed. Matched groups of hay fever patients will be compared in controlled studies of immunotherapy or new drugs. At the same time studies of leukocyte sensitivity and/or reactivity will be performed by in vitro histamine release, blocking antibody titers will be determined, specific reagins will be measured and total serum IgE determined. BIBLIOGRAPHIC REFERENCES: Norman, P.S.: Immunotherapy (Desensitization) in Allergy. Advances in Asthma and Allergy 1: 1, 1974. Norman, P.S.: Immunotherapy (Desensitization) in Allergic Diseases. Ann. Rev. Med. 26: 337, 1975.